def fn1():
    res=1/0
    print('第一层')

def fn2():
    try:
        fn1()
        print('第二层')
    except Exception as e:
        print(e)

def fn3():
    fn2()
    print('第三层')

fn3()


# def fn1():
#     res=1/0
#     print('第一层')
#
# def fn2():
#        fn1()
#        print('第二层')
#
#
# def fn3():
#     try:
#         fn2()
#         print('第三层')
#     except Exception as e:
#         print(e)

